1. Field of the Invention
The present invention relates to an ink-jet recording apparatus, and more particularly to an ink cartridge (hereinafter also referred to as an ink tank) for storing ink to be supplied to an ink-jet head, a recording unit which integrally includes the ink cartridge and the ink-jet head, which are removably connected with each other, and the ink-jet recording apparatus on which the recording unit can be removably mounted. In the following description, the term xe2x80x9crecordxe2x80x9d includes a meaning of printing characters, images or the like on cloth, paper, plastic sheet, or the like.
2. Description of Related Art
Several types of recording apparatuses on which a recording head of one""s own method such as: wire-dot method; thermal recording method; thermal-transfer method; and ink-jet method, is mounted, and which record characters, images or the like on a recording medium such as a paper, have been proposed. Among these methods, the ink-jet recording method is one of non-impact methods and includes the step of ejecting ink droplets and depositing these ink droplets on the recording medium. Thereby, a recording apparatus using a recording unit of this method can perform recording with high-speed and high-density. As a result, they have been provided as printers as output terminals of an information processing systems e.g., copying machines, facsimiles, printing machines, word processors, work stations, or the like; or they have been provided as handy- or portable-printers of personal computers, host computers, optical disc- or video- equipment or the like.
In the case of that the ink-jet recording apparatus is used in these system, the ink-jet recording apparatus is constructed so as to accord with respective particular function and condition for use of these systems. To miniaturize a size of the information processing system is one of main current demand. Accordingly, the recording unit and the main body of the ink-jet recording apparatus using this unit are demanded to be miniaturized.
While such a miniaturizing is realized on an actual apparatus base, however, it is need for the recording unit or the like to maintain performance which have been known usually in the unit or to have further performance. In order to answer these demands, there have been proposed various recording units and various recording apparatuses in which this unit is mounted.
One of the embodiments is explained first with reference to FIG. 1.
In this figure, an ink-jet unit includes an ink-jet head 102 and an ink cartridge 101 as a reservoir for storing the fluid such as ink, which are removably connected to each other. The ink-jet unit is removably mounted on a carriage 121. Also the carriage 121 is movably attached to a guide shaft and a lead screw which are supported by a main frame 122 of the ink-jet recording apparatus 120.
It is noted that the ink-jet unit is not limited to the structure described above. That is, for example, there is an ink-jet unit having an ink cartridge integrally connected with the ink-jet head. In the case of using the former type of ink-jet head, the ink cartridge is of an interchangeable type while the ink-jet head is fixed or removably mounted on the carriage.
In the case that the recording head (ink-jet head) and the ink cartridge are mounted on the carriage as described above, it is necessary to provide the ink cartridge with a mechanism of generating a negative pressure. In the description below, in general, the term xe2x80x9ca negative pressurexe2x80x9d is defined as a state of that a water head pressure of the ink is kept at a value lower than that of the atmospheric pressure enough to stop a leakage of ink from nozzles of the recording head. As a negative pressure generating mechanism provided in the ink cartridge, a porous member as an ink absorbing member is used which generates a capillary force of the porous member. In the case of using the porous member, as disclosed in the documents such as Japanese Patent Application Laying-Open No.2-187364, the ink cartridge takes the construction of that the ink inlet portion of the recording head is press-inserted into the ink absorber of the ink cartridge for increasing an efficiency of using the ink, that is, for reducing the rest amount of the ink in the ink absorber.
According to the construction described above, the capillary force of the porous member can be locally increased by deforming the ink absorber at a part thereof around the ink-inlet portion and thereby the ink is induced to the neighborhood of the ink-inlet portion and ink supply is promoted so that the rest amount of ink in the ink absorber is decreased.
In the case of the removable type recording unit (ink-jet unit), there is a possibility that the user will change the empty ink cartridge with new one. Also, there is another possibility of changing the recording head with new one or filling up the empty ink cartridge with ink to use it again. Furthermore, there is a possibility of that the user will separate them oftener than he or she have to do. Therefore, it is difficult to predict the situation on which the recording head or the ink cartridge is detached and is mounted. At the stage of the separation or connection between them, therefore, the amount of air can be allowed to enter the ink cartridge and prevents an ink route from being formed between the recording head and the ink cartridge.
The removable type recording unit as disclosed in the Japanese Patent Application Laying-Open No.2-187364, especially in the case of that the ink inlet portion of the recording head is press-inserted into the ink absorber for using the ink efficiently, has the following problems. That is, the present inventors find that the recording head is difficult to receive the ink from the ink cartridge generally in the case of after connecting the ink cartridge with the recording head, again before the ink cartridge is used up.
In this situation, the ink flow to the recording head cannot be often recovered by an ejection recovery operation with the step of sucking ink out of ejection port of the recording head and thus it is difficult to consume the ink completely. The present inventors make clear that the largest cause for such trouble in the situation described above is as follows.
FIGS. 2A and 2B illustrate one of the embodiments of the ink-jet recording apparatus for explaining such cause. FIG. 2A shows connected state of a recording head 2 with an ink cartridge 3, and FIG. 2B shows detached state of the former from the latter.
As shown in the figures, an ink-jet unit 4 is constituted by removably connecting the recording head 2 with the ink cartridge 3 by means of a pair of parallel connecting claws (not shown).
At the connection, the ink-inlet portion 40 of the recording head 2 is inserted into a cylindrical connecting portion 39 which is used as an ink supply portion. The ink path 36 can be isolated from the external atmosphere by means of the O-ring 35 which seals around the connected portion and which is made of ethylene propylene rubber or the like.
The porous member (i.e., an ink absorber such as a sponge material) 37 occupies the inner side of the ink cartridge 3 so as to store the ink to be supplied to the recording head 2. That is, the porous member has an ability of holding the ink.
Therefore, the density of the porous member is adjusted and a water-head pressure of the recording head 2 is kept to be and lower than that of the atmospheric pressure so as to avoid the ink leakage.
In the ink-jet recording head having the structure described above, a part of the ink absorber adjacent to the connecting portion 39 is directly subjected to the external atmosphere when the recording head 2 and the ink cartridge 3 are in the removed condition. In this case, while the deformed ink absorber 37 is coming back its original shape, the ink absorber 37 induces air so that the part 38 of the ink absorber 37 adjacent to the connecting portion 39 of the ink cartridge 3 can be filled with air bubbles or with bubbling ink when the recording head 2 and the ink cartridge 3 are separated from each other.
In this state, when the recording head 2 is connected to the cartridge 3, the ink absorber 37 forms an air region in the part adjacent to the ink supply portion 39. Therefore, the aired region prevents an ink route E from being formed.
Furthermore the air in the ink supply portion can be compressed into the ink absorber by inserting the ink-inlet portion 40 of the recording head 2 into the ink cartridge 3 and the compressed air also prevents the ink route E from being formed.
Under these conditions, consequently, undesirable recording state can be caused as a result of decreased amount of ink flow or the interrupted ink route.
To solve the problems described above, mechanical devices for controlling the inflow of air into the ink route have been proposed in several documents, for the example the document of European Patent Application No. 536,980. This document discloses a fibrous sleeve in a part protruding from the recording head. An inner end of the sleeve communicates with the ink chamber of the head, while an external end thereof is in contact with an ink absorber of the ink reservoir when the recording head is connected with the ink reservoir. According to the structure described above, the sleeve functions as a filter and prevent air from being induced into the chamber of the recording head.
In this document however, there is no suggestion to solve the problem of that the air gets into the ink cartridge during the period of performing the separation and the re-connection between the recording head and the ink cartridge.
Furthermore, there is an idea of providing a valve mechanism for closing the ink outlet to prevent the influx of air into the ink path during the separation and the re-connection. Comparing with the conventional recording unit, however, a process of making the recording unit having the valve mechanism requires more cost of the production and more parts, and also the resulting product can be a large-sized one with a poor performance. This results decreasing of advantage of the removable type of the recording unit.
In addition to the problem of that the air gets easily into the ink cartridge during the period of separating and re-connecting the recording head, with the ink cartridge there remains another matters to be considered in the removable type of recording unit:
(i) the ink leaks from the ink connecting portion when the recording head is removed;
(ii) the appropriate amount of ink supply from the ink cartridge to the recording head; and
(iii) an efficiency of using the ink stored in the ink cartridge.
Therefore, the present invention can solve many kind of problems described above which occur in the removable recording unit in which the recording head is detached from or connected to the ink cartridge.
The object of the present invention is to provide an ink cartridge with low cost and high reliability which prevent ink from leaking therefrom and stably supply ink after detaching and connecting between a recording head and an ink cartridge.
It is another object of the invention to provide an ink-jet recording unit having the ink cartridge described above.
It is a further object of the invention to provide an ink-jet recording apparatus using the recording unit with the ink cartridge described above.
In the first aspect of the present invention, there is provided an ink cartridge having an ink-reserving portion with a porous member for storing ink and an ink-supply portion for supplying ink from the ink-reserving portion to an outside of the ink cartridge, comprising:
an ink-inducing element which is arranged between the ink-reserving portion and the ink-supply portion, the inducing element being formed as a bundle of fibers in which each fiber is parallel to a direction of supplying the ink.
In the second aspect of the present invention, there is provided an ink cartridge having a porous member for storing ink to be supplied to a recording head through an ink-inlet portion of the recording head, comprising:
an ink-inducing element having a first end portion to be press-touched with the ink-inlet portion and a second end portion to be press-touched with the porous member, the ink-inducing element being formed as a bundle of fibers each of which is directed from the second end portion to the first end portion.
In the third aspect of the present invention, there is provided an ink cartridge comprising:
a porous member for storing ink; and
an ink-supply portion which has an outlet used for supplying ink to an ink jet head and into which an ink inlet portion of the ink jet head; the ink-supply portion having an air path for letting air to be introduced into the ink cartridge from the ink-supply portion escape to the outside of the ink cartridge when the ink-inlet portion is inserted into the ink-supply portion.
In the fourth aspect of the present invention, there is provided an ink-jet recording apparatus mounting a recording unit which has a recording head with a plurality of ejection ports; and
an ink cartridge having a porous member for storing ink, wherein the recording unit having an ink inlet portion for leading ink from the ink cartridge, and the ink cartridge having an ink inducing element one end of which is press-touched with the ink inlet portion and the other end of which is press-touched the ink absorber, and which is made of a bundle of fibers, a carriage being provided for detachably mounting the recording unit.
In the fifth aspect of the present invention, there is provided an ink-jet recording apparatus including an ink-jet recording unit which has a recording head for ejecting ink and an ink cartridge for storing, and performing recording by ejecting ink onto a recording medium, wherein the ink cartridge has an ink absorber for holding ink, and an ink inducing element disposed between the ink absorber and an outlet for supplying ink to outside, a capillary force of the ink inducing element is higher than that of the ink absorber, and also a pressure loss of the ink inducing element is 20 mmAq or under.
In the sixth aspect of the present invention, there is provided an ink jet recording apparatus using a recording unit which has a recording head for recording by ejecting ink and an ink cartridge for supplying ink to the recording head, the recording head and the ink cartridge are removably connected with each other, wherein the recording head has an ink inducing element which is press-touched to the ink cartridge and provided for receiving the ink supply, and wherein the ink cartridge has an ink absorber for storing ink to be supplied to the recording head, an ink supply portion into which an ink inlet of the recording head is inserted and which has outlet formed at front end of the ink cartridge, so as to constitute ink path communicating the ink inlet with the ink absorber, an ink inducing element one end of which is press-touched to the ink inlet inserted into the ink supply portion and another end of which is press-touched to the ink absorber, and an air communicating path disposed between the ink inducing element and a wall of the ink supply portion and provided for letting air to be introduced into the ink cartridge from the ink supply portion escape to an outside of the ink cartridge when the ink inlet portion is inserted into the ink supply portion.
In the seventh aspect of the present invention, there is provided an ink-jet recording unit including a recording head with a plurality of ejection ports for ejecting ink and an ink cartridge having a porous member for holding ink to be supplied to the recording head, wherein
the recording head has an ink inlet for lead ink from the ink cartridge,
and wherein the ink cartridge has an ink inducing element one end of which is press-touched to the ink inlet, another end of which is press-touched to the ink absorber, and which is made of a bundle of fibers in which each fiber is directed from the porous member to the ink inlet portion.
In the eighth aspect of the present invention, there is provided an ink-jet unit in which an ink jet head for ejecting ink and an ink cartridge for storing ink to be supplied to the ink jet head are removably connected with each other,
wherein the ink cartridge has an ink absorber for holding stored ink, and an ink inducing element disposed between the ink absorber and an outlet for supplying ink to an outside, a capillary force of the ink inducing element is higher than that of the ink absorber and a pressure loss of the ink inducing element is 20 mmAq or under, and an ink inlet of the ink jet head is touched to the ink inducing element.
In the ninth aspect of the present invention, there is provided a recording unit in which a recording head for recording by ejecting ink and an ink cartridge for supplying ink to the recording head which are removably connected with each other; wherein the recording head an ink inducing portion which is touched to the ink cartridge and is provided for receiving the ink supply one end of the ink inducing element being touched to the ink inlet inserted into the ink supply portion, and another end of the ink inducing element being press-touched to the ink absorber, and the ink cartridge has an ink absorber for storing ink to be supplied to the recording head, an ink supply portion into which an ink inlet of the recording head and which has an outlet formed on a front end of the ink cartridge, so as to form an ink supply route communicating the ink inducing element with the ink absorber, and air path for letting air escape to an outside, the air path being disposed between the ink inducing element and a wall of the ink supply portion when the receding head is connected with the ink cartridge.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.